In general, a hammer such as a pneumatic hammer repeatedly strikes a mass against an output member, such as a chisel. The mass may strike the output member as many as 2000 times per minute, imparting energy to the output member each time the mass strikes. In the case of a chisel output member, the energy drives the chisel against material being chiseled so the chisel cuts or breaks the material. This rapid and repeated striking also produces vibrations that are transmitted through the hammer to a user holding the hammer. The vibrations may make it difficult for the user to use the hammer for extended periods of time.